Showing papers on "Insulated-gate bipolar transistor published in 2008"

New transformerless, scalable Modular Multilevel Converters for HVDC-transmission

Abstract: In this paper a novel concept of high voltage direct current converter (HVDC) is presented employing the modular multilevel converter (M2C). Converters using IGBT-power devices, are getting increased importance in order to meet the global needs for reliable and environment friendly power supply and distribution. The new topology is compared to HVDC-transmission based on two level (2level) converters with direct series connected IGBT- devices or known multilevel converters. Main design aspects, concerning the rating of the power devices, the power losses and achievable efficiencies are investigated. For this purpose, a new computation method is presented and applied. This enables clear insight into the influence of various design parameters in a generalized form. Additionally, the characteristics and the differences of the topologies, with respect to passive filters, the necessary pulse frequencies and the arm currents are examined. As an example of the results, a comparison of the semiconductor losses and the efficiencies of the different topologies are given.

Model for Power Cycling lifetime of IGBT Modules - various factors influencing lifetime

Abstract: A large number of power cycling data from different IGBT module generations and test conditions have been evaluated. Multiple regression with respect to the variables temperature swing DeltaTJ, TJ, power-on-time (ton), chip thickness, bonding technology, diameter (D) of bonding wire, current per wire bond (I) and package type was performed. It provided parameters for a new empirical model describing number of power cycles (Nf) in relation to these variables. For a fixed module technology and blocking voltage class, the set of variables have been restricted to DeltaTJ, TJ, ton and I as the factors influencing the number of cycles to failure. The model is used to estimate the power cycling capability for the new generation of 1200V-IGBT4 Modules, which are rated up to a junction temperature of 150deg C in operation.

A Predictive Control With Flying Capacitor Balancing of a Multicell Active Power Filter

Abstract: Unlike traditional inverters, multicell inverters have the following advantages: lower switching frequency, high number of output levels, and less voltage constraints on the insulated-gate bipolar transistors. Significant performances are provided with this structure which is constituted with flying capacitors. This paper deals with a predictive and direct control applied to the multicell inverter for an original application of this converter: a three-phase active filter. To take advantage of the capabilities of the multicell converter in terms of redundant control states, a voltage control method of flying capacitor is added, based on the use of a switching table. Flying capacitor voltages are kept on a fixed interval, and precise voltage sensors are not necessary. The association of predictive control and voltage balancing increases considerably the bandwidth of the active filter.

A new Multilevel Voltage-Sourced Converter Topology for HVDC Applications

Abstract: SUMMARY Since the Seventies line commutated converters based on thyristor technology have been the standard for all HVDC applications. This converter topology is, however, marked by its loworder harmonics and high reactive power consumption. Such measures as the use of filter circuits and switchable capacitor banks have been taken to reduce these effects. On the other hand, these converters are marked by low operational losses, robustness of the thyristors against surge currents as well as their overload capability. Therefore, line-commutated thyristor technology will remain best suited to bulk power transmission in future HVDC projects. Compared with the line-commutated technology, additional inherent advantages are obtained through the use of self-commutated converters. In this kind of converter topology, current commutation is independent of the line voltage. This is the case because commutation is purely based on the turn-off capability of the power semiconductors such as IGBTs (Insulated Gate Bipolar Transistor). These semiconductors have gained in importance over the years and, due to their reliability, they are most commonly used in such challenging applications as traction and industrial drives. The VSC (Voltage-Sourced Converter) is the most common type of self-commutated converters and has therefore become a standard in the applications mentioned above. The possibility to control active and reactive power independently within weak or even passive networks makes them attractive to power transmission and distribution applications. Most VSCs are based on two-level technology along with PWM (Pulse-Width Modulation) controls. This implies that the AC connection voltage can only be switched between two possible levels which are defined by the common DC link capacitor connected to the DC terminals. Through pulse-width modulation with high switching frequencies (up to kHz range), the desired RMS voltage can be controlled and even some discrete low order harmonics can be reduced or eliminated. The use in HVDC applications requires high voltage ratings of the converter which can be achieved by a series connection of power

A T-Connected Transformer and Three-leg VSC Based DSTATCOM for Power Quality Improvement

Abstract: In this paper, a new three-phase four-wire distribution static compensator (DSTATCOM) based on a T-connected transformer and a three-leg voltage source converter (VSC) is proposed for power quality improvement. The T-connected transformer connection mitigates the neutral current and the three-leg VSC compensates harmonic current, reactive power, and balances the load. Two single-phase transformers are connected in T-configuration for interfacing to a three-phase four-wire power distribution system and the required rating of the VSC is reduced. The insulated gate bipolar transistor (IGBT) based VSC is supported by a capacitor and is controlled for the required compensation of the load current. The DC bus voltage of the VSC is regulated during varying load conditions. The DSTATCOM is tested for power factor correction and voltage regulation along with neutral current compensation, harmonic elimination, and balancing of linear loads as well as nonlinear loads. The performance of the three-phase four-wire DSTATCOM is validated using MATLAB software with its Simulink and power system blockset toolboxes.

An IGBT Gate Driver for Feed-Forward Control of Turn-on Losses and Reverse Recovery Current

Abstract: This paper addresses the problem of turn on performances of an insulated gate bipolar transistor (IGBT) that works in hard switching conditions. The IGBT turn on dynamics with an inductive load is described, and corresponding IGBT turn on losses and reverse recovery current of the associated freewheeling diode are analysed. A new IGBT gate driver based on feed-forward control of the gate emitter voltage is presented in the paper. In contrast to the widely used conventional gate drivers, which have no capability for switching dynamics optimisation, the proposed gate driver provides robust and simple control and optimization of the reverse recovery current and turn on losses. The collector current slope and reverse recovery current are controlled by means of the gate emitter voltage control in feed-forward manner. In addition the collector emitter voltage slope is controlled during the voltage falling phase by means of inherent increase of the gate current. Therefore, the collector emitter voltage tail and the total turn on losses are significantly reduced. The proposed gate driver was experimentally verified and compared to a conventional gate driver, and the results are presented and discussed in the paper.

Design of a Back-to-Back NPC Converter Interface for Wind Turbines With Squirrel-Cage Induction Generator

Abstract: As the number of wind power applications with power electronic interfaces in the grid increases, it is becoming unacceptable to disconnect the generating units every time disturbances occur, especially under voltage dips, as was a common practice in the past. Keeping the converter online during unbalanced voltage, and guaranteeing the actual standards of the converter connected to the grid, is becoming a very critical issue. From these goals, the design of a robust back-to-back neutral point clamped (three levels) voltage source converter of 150 kVA is developed in this paper. The converter is divided into two main parts: the power electronic system and the control electronic system. Concerning the first part, on the one hand, the paper presents the designs of active and passive components as insulated gate bipolar transistor, free-wheeling diodes, clamping diodes, grid filter, DC-bus capacitors, etc.; and on the other hand, the converter requirements are analyzed to ride through real grid conditions, i.e., unbalanced voltage dips. Concerning the control electronic system, the chosen electronic structure and the task distribution between the two processors used are shown.

Active Gate Control for Current Balancing of Parallel-Connected IGBT Modules in Solid-State Modulators

Abstract: In modern pulsed power systems, often, fast solid-state switches like MOSFETs and insulated gate bipolar transistor (IGBT) modules are used to generate short high power pulses. In order to increase the pulsed power, solid-state switches have to be connected in series or in parallel. Depending on the interconnection of the switches, parameter variations in the switches and in the system can lead to an unbalanced voltage or current. Therefore, the switches are generally derated, which results in an increased number of required devices, cost, and volume. With an active gate control, derating and preselection of the switching devices can be avoided. In this paper, an active gate control of paralleled IGBT modules, which has been developed for converters with inductive load, is explained in detail and adapted to a solid-state modulator. This paper focuses on achieving a low-inductance IGBT current measurement, the control unit implementation with a field-programmable gate array and a digital signal processor, as well as the balancing of the pulse currents.

Transient Stability Augmentation of Power System Including Wind Farms by Using ECS

Abstract: This paper presents a new method to enhance the transient stability of multimachine power system including wind farms, when a severe network disturbance occurs in the power system. For this purpose, the energy capacitor system (ECS) composed of power electronic devices and electric double layer capacitor (EDLC) is proposed. The control scheme of ECS is based on a sinusoidal PWM voltage source converter (VSC) and fuzzy logic controlled dc-dc buck/boost converter using insulated gate bipolar transistors (IGBT). Two wind farms are considered to be connected to the power system. Two-mass drive train model of wind turbine generator system (WTGS) is used in the analyses as the drive train modeling has great influence on the dynamic characteristics of WTGS. Real wind speed data are used in the analyses to obtain realistic responses. Different types of symmetrical and unsymmetrical faults are considered as the network disturbance. Simulation results clearly show that the proposed ECS can enhance the transient stability of wind generators in multimachine power system as well as their low voltage ride through (LVRT) capability.

An agile accelerated aging, characterization and scenario simulation system for gate controlled power transistors

Abstract: To advance the field of electronics prognostics, the study of transistor fault modes and their precursors is essential. This paper reports on a platform for the aging, characterization, and scenario simulation of gate controlled power transistors. The platform supports thermal cycling, dielectric over-voltage, acute/chronic thermal stress, current overstress and application specific scenario simulation. In addition, the platform supports in-situ transistor state monitoring, including measurements of the steady-state voltages and currents, measurements of electrical transient response, measurement of thermal transients, and extrapolated semiconductor impedances, all conducted at varying gate and drain voltage levels. The aging and characterization platform consists of an acquisition and aging hardware system, an agile software architecture for experiment control and a collection of industry developed test equipment.

Identification of failure precursor parameters for Insulated Gate Bipolar Transistors (IGBTs)

Abstract: Insulated Gate Bipolar Transistors (IGBTs) are used in applications such as the switching of automobile and train traction motors, high voltage power supplies, and in aerospace applications such as switch mode power supplies (SMPS) to regulate DC voltage. The failure of these switches can reduce the efficiency of the system or lead to system failure. By identifying failure precursor parameters in IGBTs and monitoring them, a prognostics methodology can be developed to predict and avert failures. In this study, IGBTs aged by thermal-electrical stresses were evaluated in comparison with new components to determine the electrical parameters that change with stressing. Three potential precursor parameter candidates, threshold voltage, transconductance, and collector-emitter (ON) voltage, were evaluated by comparing aged and new IGBTs under a temperature range of 25-200degC. The trends in the three electrical parameters with temperature were correlated to device degradation. A methodology is presented for validating these precursor parameters for IGBT prognostics.

Commercial Frequency AC to High Frequency AC Converter With Boost-Active Clamp Bridge Single Stage ZVS-PWM Inverter

Abstract: This paper presents a novel soft-switching pulsewidth modulation (PWM) utility frequency ac to high frequency (HF) ac power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented using the switching mode equivalent circuits in addition to the operating voltage and current waveforms. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching operation ranges and the power dissipation loss analysis as compared with those of the previously developed high frequency inverter. In addition, a dual mode selected control scheme of this high frequency inverter based on a constant frequency asymmetrical PWM and pulse density modulation control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The practical effectiveness of this power frequency converter is substantially proved on the basis of experimental results from practical design example.

How to Select the System Voltage of MV Drives—A Comparison of Semiconductor Expenses

Abstract: The application of a particular medium-voltage converter in a certain application depends on numerous criteria. However, in completely new installations, the choice of the system voltage is very often uninhibited of external constraints. Then, the voltage level shall be selected to enable the most efficient power conversion at the lowest cost. This paper is dedicated to help in finding the best voltage level for three-level neutral-point-clamped voltage source converters (3L-NPC VSCs) with respect to the power semiconductor devices. Three insulated-gate-bipolar-transistor-based 3L-NPC VSCs of different voltage levels (2.3, 3.3, and 4.16 kV) are investigated and compared regarding their maximum output power, semiconductor efficiency, and semiconductor cost per MVA output power. The effects of thermal cycling, the loss distribution within the converter, and switching frequencies from 300 to 1050 Hz are considered in the evaluation.

A 13 kV 4H-SiC n-Channel IGBT with Low Rdiff,on and Fast Switching

Abstract: For the first time, high power 4H-SiC n-IGBTs have been demonstrated with 13 kV blocking and a low Rdiff,on of 22 mWcm2 which surpasses the 4H-SiC material limit for unipolar devices. Normally-off operation and >10 kV blocking is maintained up to 200oC base plate temperature. The on-state resistance has a slight positive temperature coefficient which makes the n-IGBT attractive for parallel configurations. MOS characterization reveals a low net positive fixed charge density in the oxide and a low interface trap density near the conduction band which produces a 3 V threshold and a peak channel mobility of 18 cm2/Vs in the lateral MOSFET test structure. Finally, encouraging device yields of 64% in the on-state and 27% in the blocking indicate that the 4H-SiC n-IGBT may eventually become a viable power device technology.

A High Current 3300V Module Employing Reverse Conducting IGBTs Setting a New Benchmark in Output Power Capability

Abstract: In this paper we demonstrate a fully functional high voltage and high current IGBT module rated at 3300 V consisting solely of reverse conducting (RC) IGBT chips. The RC- IGBTs were designed in accordance with the latest Enhanced Planar and Soft Punch Through technology while incorporating an integrated freewheeling diode in the same silicon volume. Future high power IGBT modules with RC-IGBT technology will be capable of providing exceptional electrical performance for the given voltage class in terms of the maximum allowable output current capability.

Optimization of on -State and Switching Performances for 15–20-kV 4H-SiC IGBTs

Abstract: The 4H-SiC p-channel IGBTs designed to block 15 and 20 kV are optimized for minimum loss (on-state plus switching power) by adjusting the parameters of the JFET region, drift layer, and buffer layer, using 2-D MEDICI simulations. Switching loss exhibits a strong dependence on buffer layer thickness, doping, and lifetime due to their influence on the current tail. In contrast, drift layer lifetime has little effect on the crossover frequency at which the MOSFET and IGBT have equal loss.

12-kV p-Channel IGBTs With Low On-Resistance in 4H-SiC

Abstract: SiC bipolar devices are favored over SiC unipolar devices for applications requiring breakdown voltage in excess of 10 kV. We have designed and fabricated p-channel insulated-gate bipolar transistors (IGBTs) in 4H-SiC with 12-kV blocking voltage for high-power applications. A differential on-resistance of 18.6 mOmega ldr cm2 was achieved with a gate bias of 16 V, corresponding to a forward voltage drop of 5.3 V at 100 A/cm2, indicating strong conductivity modulation in the p-type drift region. A moderately doped current enhancement layer grown on the lightly doped drift layer effectively reduces the JFET resistance while maintaining a high carrier lifetime for conductivity modulation. The p-channel IGBT (p-IGBT) exhibits a transconductance that is 3times higher than that of the 12-kV n-channel SiC IGBTs. An inductive switching test was done at 1.5 kV and 0.55 A (~440 A/cm2) for the p-IGBTs, and a turn-on time of 40 ns and a turn-off time of ~2.8 mus were measured.

Characterization and Comparison of High Blocking Voltage IGBTs and IEGTs Under Hard- and Soft-Switching Conditions

Abstract: The market of converters connected to transmission lines continues to require insulated gate bipolar transistors (IGBTs) with higher blocking voltages to reduce the number of IGBTs connected in series in high-voltage converters. To cope with these demands, semiconductor manufactures have developed several technologies. Nowadays, IGBTs up to 6.5-kV blocking voltage and IEGTs up to 4.5-kV blocking voltage are on the market. However, these IGBTs and injection-enhanced gate transistors (IEGTs) still have very high switching losses compared to low-voltage devices, leading to a realistic switching frequency of up to 1 kHz. To reduce switching losses in high-power applications, the auxiliary resonant commutated pole inverter (ARCPI) is a possible alternative. In this paper, switching losses and on-state voltages of NPT-IGBT (3.3 kV-1200 A), FS-IGBT (6.5 kV-600 A), SPT-IGBT (2.5 kV-1200 A, 3.3 kV-1200 A and 6.5 kV-600 A) and IEGT (3.3 kV-1200 A) are measured under hard-switching and zero-voltage switching (ZVS) conditions. The aim of this selection is to evaluate the impact of ZVS on various devices of the same voltage ranges. In addition, the difference in ZVS effects among the devices with various blocking voltage levels is evaluated.

Semiconductor device having diode-built-in IGBT and semiconductor device having diode-built-in DMOS

Abstract: A semiconductor device includes: a semiconductor substrate; a diode-built-in insulated-gate bipolar transistor having an insulated-gate bipolar transistor and a diode, which are disposed in the substrate, wherein the insulated-gate bipolar transistor includes a gate, and is driven with a driving signal input into the gate; and a feedback unit for detecting current passing through the diode. The driving signal is input from an external unit into the feedback unit. The feedback unit passes the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects no current through the diode, and the feedback unit stops passing the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects the current through the diode.

New Protection Circuit for High-Speed Switching and Start-Up of a Practical Matrix Converter

Abstract: The matrix converter (MC) presents a promising topology that needs to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the market. Taking into consideration that the great majority of efforts are being oriented toward control algorithms and modulation, this paper focuses on MC hardware. In order to improve the switching speed of the MC and thus obtain signals with less harmonic distortion, several different insulated-gate bipolar transistor (IGBT) excitation circuits are being studied. Here, the appropriate topology is selected for the MC, and a recommended configuration is selected, which reduces the excursion range of the drivers, optimizes the switching speed of the IGBTs, and presents high immunity to common-mode voltages in the drivers. Inadequate driver control can lead to the destruction of the MC due to its low ride-through capability. Moreover, this converter is especially sensitive during start-up, as, at that moment, there are high overcurrents and overvoltages. With the aim of finding a solution for starting up the MC, a circuit is presented (separate from the control software), which ensures correct sequencing of supplies, thus avoiding a short circuit between input phases. Moreover, it detects overcurrent, connection/disconnection, and converter supply faults. Faults cause the circuit to protect the MC by switching off all the IGBT drivers without latency. All this operability is guaranteed even when the supply falls below the threshold specified by the manufacturers for the correct operation of the circuits. All these features are demonstrated with experimental results. Lastly, an analysis is made of the interaction that takes place during the start-up of the MC between the input filter, clamp circuit, and the converter. A variation of the clamp circuit and start-up strategy is presented, which minimizes the overcurrents that circulate through the converter. For all these reasons, it can be said that the techniques described in this paper substantially improve the MC start-up cycle, representing a step forward toward the development of reliable MCs for real applications.

Bipolar transistor drivers

Abstract: We describe a switching power converter comprising a bipolar switching device (BJT or IGBT) switching an inductive load, and including a closed-loop control system. The control system comprises a voltage sensing system to sense a voltage on a collector terminal of the switching device and provide a voltage sense signal; a controller; and a drive modulation system coupled to an output of the controller for modulating a drive to the control terminal of said bipolar switching device responsive to a controller control signal; wherein said controller is configured to monitor changes in the sensed voltage during a period when said switching device is switched on and to control said drive modulation system to control the degree of saturation of said bipolar switching device when the device is switched on and hence improve turn-off times.

Design and Characterization of High-Voltage 4H-SiC p-IGBTs

Abstract: High-voltage p-channel 4H-SiC insulated gate bipolar transistors (IGBTs) have been fabricated and characterized. The devices have a forward voltage drop of 7.2 V at 100 A/cm2 and a -16 V gate bias at 25degC, corresponding to a specific on-resistance of 72 mOmega ldr cm2 and a differential on-resistance of 26 mmOmega ldr cm2. Hole mobility of 12 cm2/V ldr s in the inversion channel with a threshold voltage of -6 V was achieved by optimizing the n+ well doping profile and gate oxidation process. A novel current enhancement layer was adopted to reduce the JFET resistance and enhance conductivity modulation by improving hole current spreading and suppressing the electron current conduction through the top n-p-n transistor. Inductive switching results have shown that the p-IGBT exhibited a turn-off time of ~1 mus and a turn-off energy loss of 12 m J at 4-kV dc-link voltage and 6-A load current at 25degC. The turn-off trajectory from the measured inductive load switching waveforms and numerical simulations shows that the p-IGBT had a near-square reverse bias safe operating area. Numerical simulations have been conducted to achieve an improved tradeoff between forward voltage drop and switching off energy by investigating the effects of drift layer lifetime and p-buffer layer parameters. The advantages of SiC p-IGBTs, such as the potential of very low ON-state resistance, slightly positive temperature coefficient, high switching speed, small switching losses, and large safe operating area, make them suitable and attractive for high-power high-frequency applications.

Power semiconductor chip, power semiconductor module, inverter apparatus, and inverter-integrated motor

Abstract: Provided is an inverter-integrated motor including a motor and an inverter integrated in an efficient manner. Also provided is a semiconductor chip that can be used in this motor. An IGBT chip is constructed with an emitter terminal being provided at the apex of one face of a die having a regular triangular surface shape, a gate terminal being provided adjacent the opposite side to the apex, and a collector terminal being provided on the other face. A power semiconductor module is constructed with placing apices of the IGBT chips having the emitter terminals in abutment against each other. Six such power semiconductor chips are arranged in a regular hexagonal pattern to together constitute an inverter for converting DC power into three-phase AC power.

IGBT packaging and cooling using PCM and liquid

Abstract: A power control system may use power semiconductor devices such as insulated gate bipolar transistors (IGBT's) in a switching unit to provide motor control. The IGBT's may be cooled with a system that is configured and sized to provide proper cooling at steady-state operating conditions of the switching unit. The IGBT's may be placed in thermal communication with a compartment that may contain phase change material (PCM). When and if the switching unit is operated under transient high load conditions, excess heat may be absorbed by melting of the PCM. When steady state operating conditions are restored the PCM may solidify and release its latent heat to a coolant. The PCM may thus act as a thermal buffer for the cooling system and thus may provide that the cooling system may be minimally sized.

Test Bench for Grid Code Simulations for Multi-MW Wind Turbines, Design and Control

Abstract: The hardware configuration and control methodology for a test bench for power grid simulations for multi-MW wind energy applications are described. The variable voltage is generated using two (four in the final stage) medium voltage, three-phase, three-level voltage source converters with press-pack insulated gate bipolar transistors and a specially designed step-up transformer. This system differs fundamentally from known grid simulation test benches that almost always use switched inductances. Simulation results using MATLAB/Simulink and measurements as well as constraints to the system are discussed.

Power factor correction circuit

Abstract: A power factor correction circuit having an input current for reducing the distortion and harmonics generated in a power line feeding power supply. The power factor correction circuit includes a control switch (such as an IGBT) for producing a control switch current and virtual short circuit; a load for acting as power demand from a load and producing a load current; and one or more of resistors for measuring current within said circuit.

A Specific Filter for Eliminating High-Frequency Leakage Current From the Grounded Heat Sink in a Motor Drive With an Active Front End

Abstract: This paper addresses a specific filter for integration into a motor drive system with an active front end. Three circuit configurations are investigated with focus on the high-frequency leakage current flowing out of a common grounded heat sink for two insulated-gate bipolar transistor modules. The motor drive system used in this experiment consists of a voltage-source pulsewidth modulation rectifier and inverter with the same carrier frequency as 14 kHz, together with an interior permanent magnet synchronous motor (IPM-SM) rated at 190 V and 5.5 kW. Experimental waveforms, along with putting an interpretation on their filtering performance, lead to the best filter configuration among the three.

5kV/200ns Pulsed Power Switch based on a SiC-JFET Super Cascode

Abstract: In many pulse power applications there is a trend to modulators based on semiconductor technology. For these modulators high voltage and high current semiconductor switches are required in order to achieve a high pulsed power. Therefore, often high power IGBT modules or IGCT devices are used. Since these devices are based on bipolar technology the switching speed is limited and the switching losses are higher. In contrast to bipolar devices unipolar ones (e.g. SiC JFETs) basically offer a better switching performance. Moreover, these devices enable high blocking voltages in case large bandgap materials as SiC are used. At the moment SiC JFET devices with a blocking voltage of 1.5 kV per JFET are available. Alternatively, the operating voltage could be increased by connecting N JFETs and a low voltage MOSFET in series resulting in a Super Cascode switch with a blocking voltage N-times higher than the blocking voltage of a single JFET. In order to evaluate the achievable switching speed of the Super Cascode and its applicability in solid state modulators, the performance of such a SiC switch is examined in this paper. Furthermore, the performance of the Super Cascode is compared with 4.5 kV IGBTs made by Powerex, which are mounted in a special low inductive housing for minimising the rise and fall times.

CSTBT (III) as the next generation IGBT

Abstract: Recently, the performance of Si power devices gradually approaches the physical limit, and the latest SiC device seemingly has the ability to substitute the Si insulated gate bipolar transistor (IGBT) in 1200 V class. In this paper, we demonstrate the feasibility of further improving the Si IGBT based on the new concept of CSTBTtrade. In point of view of low turn-off loss and high uniformity in device characteristics, we employ the techniques of fine-pattern and retro grade doping in the design of new device structures, resulting in significant reduction on the turn-off loss and the VGE(th) distribution, respectively.

Driving circuit for power semiconductor element

Abstract: Provided is a driving circuit which suppresses a surge voltage at the time of switching a power semiconductor element and reduces switching loss. An element (10) such as an IGBT and another element (20) to be paired are connected, the element (10) is driven by a driver (22), and a gate voltage is controlled by a control circuit (24). When the power semiconductor element is turned off, a comparator (26) detects that a voltage (Vak) of the element (20) is a prescribed voltage, the control circuit (24) switches gate resistance from low resistance to high resistance to suppress the surge voltage, and the switching loss is reduced. When the power semiconductor element is turned on, start up of the voltage (Vak) is detected, and the control circuit (24) switches the gate resistance from high resistance to low resistance after a prescribed time to suppress the surge voltage, and the switching loss is reduced.